Although you're likely to find yourself in the center of cities with public transportation or taxi services around, if you're planning a trip to Germany and expect to drive while there, you may need an international driver's permit in order to rent a car and complete your trip.
Exploring Germany by car unlocks a whole new itinerary for your trip—be it for business or pleasure—as well as flexibility for your schedule and plenty of opportunities for discovery. Business travelers may decide to rent a car to make it easier to travel to meetings in different cities while the casual adventurer might want to check out some destinations off the beaten, public transportation paths.
While Germany does not require foreign citizens to acquire international driver's permits, the neighboring country of Austria and many other European countries do. So, if you're planning to stay within Germany's borders on your drive, all you'll need is your valid United States license to rent a car, but if you're planning to travel elsewhere it would benefit you to acquire one of these permits before you go.
International Driver's Permit
In order to get an international driver's permit to operate motor vehicles in countries outside the United States, you must first have a valid U.S. driver's license as this document is essentially a translation of your existing license into different languages.
An international driver's permit provides basic information to car rental companies and local authorities overseas including your name, photograph, address, and country of residence (and state where the license was issued).
In the United States, drivers may obtain an international driver's permit at AAA offices as well as the Department of Motor Vehicles; you must, however, be 18 years of age or older to apply for one.
Extended Stays and Driving Tips
If you're going to be staying in Germany for an extended period of time (longer than a few months), you may want to consider getting a German driver's license instead as all non-European visitors must get a German driver's license after six months.
Luckily, a significant number of American states have reciprocity agreements with the German government, meaning that you can simply show the right identification at the German equivalent of the DMV to obtain a German license. For those who live in other states without reciprocity, you will only have to take a written test to get your full German license.
In any case, and as with any trip, it's best to investigate and plan before you go as it will save you both time and hassles.